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Wyszukujesz frazę "Cho, Ju-Young" wg kryterium: Autor


Wyświetlanie 1-5 z 5
Tytuł:
Effect of Deformation Temperature on the Magnetic Properties of PrFeB Alloy Fabricated by Gas Atomization
Autorzy:
Cho, Ju-Young
Song, Myung-Suk
Choa, Yong-Ho
Kim, Taek-Soo
Powiązania:
https://bibliotekanauki.pl/articles/2049154.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
PrFeB alloy
gas atomization
plastic deformation
rolling
REFeB magnet
Opis:
To form the fine micro-structures, the Pr17Fe78B5 magnet powders were produced in the optimized gas atomization conditions and it was investigated that the formation of the textures, microstructures, and the changes in the magnetic properties with increasing the deformation temperatures and rolling directions. Due to the rapid cooling system than the casting process, the homogenous microstructures were composed of the Pr-rich and Pr2Fe14B without any oxides and α-Fe and enables grain refinement. The pore ratios were 2.87, 1.42, and 0.22% at the deformation temperatures of 600, 700, 800°C, respectively in the rolled samples to align the c-axis which is the magnetic easy axis. Because Pr-rich phase cannot flow into the pore with a liquid state at low temperature, the improvement of pore densification was gradually observed with increasing deformation temperature. To confirm the magnetic decoupling effects of Pr2Fe14B phases by Pr-rich phases, the magnetic properties were investigated in rolled samples produced at the deformation temperature of 800°C. Although the remanent field is slightly decreased by 30%, the coercivity fields increased by about 2 times than that previous casted ingot. It is suggested that the gas atomization method can be suitable for fabricating grain refined and pure PrFeB magnets, and the plastic deformation conditions and rolling directions are a critical role to manipulate microstructure and magnetic properties.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 4; 955-958
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Powder Size on the Microstructure and Magnetic Properties of Nd-Fe-B Magnet Alloy
Autorzy:
Cho, Ju-Young
Abbas, Sardar Farhat
Choa, Yong-Ho
Kim, Taek-Soo
Powiązania:
https://bibliotekanauki.pl/articles/353634.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Nd-Fe-B
gas atomization
powder size
crystal orientation
hot deformation
Opis:
Rare earth Nd-Fe-B, a widely used magnet composition, was synthesized in a shape of powders using gas atomization, a rapid solidification based process. The microstructure and properties were investigated in accordance with solidification rate and densification. Detailed microstructural characterization was performed by using scanning electron microscope (SEM) and the structural properties were measured by using X-ray diffraction. Iron in the form of α-Fe phase was observed in powder of about 30 μm. It was expected that fraction of Nd2 Fe14 B phase increased rapidly with decrease in powder size, on the other hand that of α-Fe phase was decreased. Nd-rich phase diffused from grain boundary to particle boundary after hot deformation due to capillary action. The coercivity of the alloy decreased with increase in powder size. After hot deformation, Nd2 Fe14 B phase tend to align to c-axis.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 2; 623-626
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Temperature on the Plastic Deformability of Gas Atomized NdFeB Anisotropic Magnets
Autorzy:
Cho, Ju-Young
Choa, Yong-Ho
Nam, Sun-Woo
Rasheed, Mohammad Zarar
Kim, Taek-Soo
Powiązania:
https://bibliotekanauki.pl/articles/351923.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
NdFeB permanent magnet
stoichiometric composition
gas atomization
plastic deformability
crystal orientation
Opis:
NdFeB anisotropic sintered permanent magnets are typically fabricated by strip casting or melt spinning. In this study, the plastic deformability of an NdFeB alloy was investigated to study the possibility of fabricating anisotropic sintered magnets using gas atomized powders. The results show that the stoichiometric composition Nd12Fe82B6 softens at high temperatures. The aspect ratio and orientation factor of Nd12Fe82B6 billets after plastic deformation were found to increase with increasing plastic deformation temperature, particularly above 800°C. This confirms that softening at high temperatures can lead to plastic deformation of Nd2Fe14B hard magnetic phases.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 4; 1293-1296
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Evolution During Extraction and Recovery of Pure Nd from Magnet
Autorzy:
Rasheed, Mohammad Zarar
Nam, Sun-Woo
Lee, Sang-Hoon
Park, Sang-Min
Cho, Ju-Young
Kim, Taek-Soo
Powiązania:
https://bibliotekanauki.pl/articles/2048880.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Liquid Metal Extraction
rare earth recycling
vacuum distillation
phase transformation
Opis:
Liquid Metal Extraction process using molten Mg was carried out to obtain Nd-Mg alloys from Nd based permanent magnets at 900°C for 24 h. with a magnet to magnesium mass ratio of 1:10. Nd was successfully extracted from magnet into Mg resulting in ~4 wt.% Nd-Mg alloy. Nd was recovered from the obtained Nd-Mg alloys based on the difference in their vapor pressures using vacuum distillation. Vacuum distillation experiments were carried out at 800°C under vacuum of 2.67 Pa at various times for the recovery of high purity Nd. Nd having a purity of more than 99% was recovered at distillation time of 120 min and above. The phase transformations of the Nd-Mg alloy during the process, from Mg12Nd to α-Nd, were confirmed as per the phase diagram at different distillation times. Pure Nd was recovered as a result of two step recycling process; Liquid Metal Extraction followed by Vacuum Distillation.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 4; 1001-1005
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Mg Ratio on the Extraction of Dy from (Nd,Dy)-Fe-B Permanent Magnet Using Liquid Mg
Autorzy:
Park, Sang-Min
Nam, Sun-Woo
Cho, Ju-Young
Lee, Sang-Hoon
Hyun, Seung-Keun
Kim, Taek-Soo
Powiązania:
https://bibliotekanauki.pl/articles/353657.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
dysprosium
liquid metal extraction
(Nd,Dy)-Fe-B magnet
extraction behavior
diffusion
Opis:
Recently, since the demand of rare earth permanent magnet for high temperature applications such as an electric motor has increased, dysprosium (Dy), a heavy rare earth element, is becoming important due to severe bias in its production. To fulfillthe increasing need of Dy, recycling offers as a promising alternative. In recycling of rare earths, Hydro-metallurgical extraction method is mainly used however it has adverse environmental effects. Liquid metal extraction on the other hand, is an eco-friendly and simple method as far as the reduction of rare earth metal oxide is concerned. Therefore, liquid metal extraction was studied in this research as an alternative to the hydro-metallurgical recycling method. Magnesium (Mg) is selected as solvent metal because it doesn’t form intermetallic compounds with Fe, B and has a low melting and low boiling point. Extraction behavior of Dy in (Nd,Dy)-Fe-B magnet is observed and effect of Mg ratio on extraction of Dy is confirmed.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 4; 1281-1285
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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